An interconnect system is a system by which information is communicated between distinct entities, such as between computer chips on a printed circuit board (PCB) or multi-chip module (MCM). The term “interconnect”, when used as a noun, refers to the medium by which the information is communicated. An interconnect may be an electrical connection, such as a wire or signal trace on a PCB or MCM, an optical connection, such as an optical fiber, or a wireless connection, such as a radio-frequency link. As used herein, however, the term “interconnect system” refers to a system that communicates information or data via a physical, electrical connection.
A binary interconnect system transmits information by imposing one of two possible states onto each interconnect. For example, a binary interconnect system may impose one of two voltages onto each interconnect, or may impose current through the interconnect, where the current is one of two levels or one of two directions. In a binary interconnect system, the two possible states may represent two logical values, e.g., logical zero and logical one.
A multi-mode interconnect (MMI) system transmits information by coding bits onto a set of levels distributed through a multi-channel interconnection, such as a wire bundle containing more than 2 wires. This approach uses modal decomposition to formulate a CODEC that eliminates noise by generating signals that use only fundamental modes of propagation in the transmission line bundle. MMI uses encoding and decoding matrices, referred to as T and T−1, respectively that constitute the diagonal LC matrix that represents the self-inductances and capacitances of the transmission lines that make up the multichannel interconnect. The key to crosstalk cancellation is the selection of T and T−1 such that the signals are transmitted only using the fundamental eigenmodes of the ZY and YZ matrices, where Z is the per-unit-length impedance matrix and Y is the per-unit-length admittance matrix.
FIG. 1 is a block diagram illustrating a conventional multimode interconnect implementation 100, which includes an encoder 102, a multichannel interconnect 104, and a decoder 106. Encoder 102 encodes transmit binary data 108 into transmitted MM data 110, which is sent through interconnect 104. At the other end of interconnect 104, received MM data 112 includes distortion caused by cross-talk within interconnect 104. Received MM data 112 is decoded by decoder 106 to create received binary data 114, which is a recreation of transmit binary data 108.
There are disadvantages to conventional multimode interconnect systems, however. The entities on each side of interconnect 104 must agree on an encoding/decoding scheme, and each entity has the burden to perform its part and to perform it correctly. Conventional systems such as the one illustrated in FIG. 1 divide that burden, with the transmitter responsible for encoding and the receiver responsible for decoding. Such systems are herein referred to as “symmetric”, because each side has part of the burden and because the two parts have to be compatible with each other, i.e., the decoder used by the receiver must be the inverse of the encoder used by the transmitter. In symmetric systems, both transmitter and receiver must have the capability to perform what may be complex or computationally expensive encoding and decoding operations, respectively. Moreover, modification of the algorithm used at one end of the interconnect usually requires a similar modification at the other end of the interconnect. Because of this, any change to one of the transmitter/receiver pair of devices usually forces a change to the other of the pair of devices. This results in a tendency for the protocols, transforms, algorithms and/or mathematical operations surrounding interconnects to be static and may even hinder efforts to develop better algorithms.
Accordingly, in light of these disadvantages associated with conventional, symmetric multimode interconnect, there exists a need for methods, systems, and computer readable media for asymmetric multimode interconnect.